Human Antibody Response to Schistosoma mansoni Surface Antigens Defined by Protective Monoclonal Antibodies

The antibody response to a 38,000-dalton schistosomular surface antigen, defined by a rat protective monoclonal antibody and specific for Schistosoma species, has been studied in a group of 125 Brazilian patients with schistosomiasis. Antibodies binding this particular antigen were detected in 97% of patient serum samples, a result suggesting that it could represent a potent immunogen. Quantitative studies of the amount of isolated antigens were performed in relation to the age of patients. Results showed a maximal response in the second decade of life and correlated with previous observations on the prevalence and intensity of schistosomiasis. However, in the present study no relationship was shown between the binding capacity of sera and the number of schistosomal eggs in individual patients. These data suggest that the antibody response to the 38,000-dalton schistosomular antigen could be a marker of infection by schistosomes.